Function declaration
```JavaScript
function doMagic () {
  console.log('I'm a function declaration')
}
```
Function expressions
```JavaScript
var x = function () {
  console.log('I'm an anonymous function expression')
}

var y = function doMagic () {
  console.log('I'm a named function expression')
}

(function () {
  console.log('I'm a self-invoking function expression')
})()

(function doMagic () {
  console.log('I'm a named self-invoking function expresion')
})()

setTimeout(function () {
  console.log('I'm also an anonymous function expression)
}, 1000);

setTimeout(function timeoutHandler () {
  console.log('I'm also a named function expression)
}, 1000);

```